Need advice on converting AC system
05-23-2016, 08:31 PM
#16
Burning Brakes
Thread Starter
Have an AC shop flush the system *before* you replace the old compressor.
When you get the compressor, turn it upsidedown to drain the oil that is in it.
Let it drain for a long time.
Then refill with R134a compatible oil, and put the new compressor in the car.
Do all the o-rings, there are only a handful of them and they are easy enough to do.
Have the shop (or you) pull a vacuum on the system to 25+ inches and then watch the gauge for any leaks with the vac pump off.
If no leaks, then the vacuum in the system will help pull in some R134 to the system. Start the car, turn the AC on full, and fill the system with R134 until the compressor engages, the pressure on the gauge should go down momentarily. Keep filling the system until you have ~30-40psi low side and 150-250psi high side pressure, and you have used 30 oz of R134a (2.5 cans) if you have an early car or 924S.
When you get the compressor, turn it upsidedown to drain the oil that is in it.
Let it drain for a long time.
Then refill with R134a compatible oil, and put the new compressor in the car.
Do all the o-rings, there are only a handful of them and they are easy enough to do.
Have the shop (or you) pull a vacuum on the system to 25+ inches and then watch the gauge for any leaks with the vac pump off.
If no leaks, then the vacuum in the system will help pull in some R134 to the system. Start the car, turn the AC on full, and fill the system with R134 until the compressor engages, the pressure on the gauge should go down momentarily. Keep filling the system until you have ~30-40psi low side and 150-250psi high side pressure, and you have used 30 oz of R134a (2.5 cans) if you have an early car or 924S.
Couple more questions. My new compressor comes with ester oil so I'm assuming I won't need to drain it??
Also once the car is flushed and I remove the old compressor and dryer to install the new units, does the system need to reflush because I opened up the lines to put my new stuff on?
05-23-2016, 08:59 PM
#17
Rainman
Rennlist Member
Rennlist Member
I don't recall off hand but if ester is R134a OK then you're fine.
I put a reman Nippondenso in 2 years ago and drained/re-filled it for peace of mind.
no need to reflush
I put a reman Nippondenso in 2 years ago and drained/re-filled it for peace of mind.
no need to reflush
05-23-2016, 10:25 PM
#18
Here is the Porsche guide:
http://944time.com/porsche/2005images/944_ac.pdf
From http://944time.com/porsche/944-ac-air-conditioning.php
But don't put R134A adapters on! You can't fit one on the compressor.
Use a R12 hose set. You can fill it with R-134A thru the R12 style schrader valves.
http://944time.com/porsche/2005images/944_ac.pdf
From http://944time.com/porsche/944-ac-air-conditioning.php
But don't put R134A adapters on! You can't fit one on the compressor.
Use a R12 hose set. You can fill it with R-134A thru the R12 style schrader valves.
05-23-2016, 10:26 PM
#19
Rainman
Rennlist Member
Rennlist Member
Here is the Porsche guide:
http://944time.com/porsche/2005images/944_ac.pdf
From http://944time.com/porsche/944-ac-air-conditioning.php
But don't put R134A adapters on! You can't fit one on the compressor.
Use a R12 hose set. You can fill it with R-134A thru the R12 style schrader valves.
http://944time.com/porsche/2005images/944_ac.pdf
From http://944time.com/porsche/944-ac-air-conditioning.php
But don't put R134A adapters on! You can't fit one on the compressor.
Use a R12 hose set. You can fill it with R-134A thru the R12 style schrader valves.
Or buy this one on Ebay.
http://www.ebay.com/itm/Charging-Ada...-/400303092837
05-25-2016, 08:02 PM
#20
Burning Brakes
Thread Starter
Need circus freaks!!!
Ok, which one of you circus freaks know how to get your hands down and in the engine compartment next to the firewall to unbolt the AC lines that go into the firewall on a 951. My man hands cannot get a tool down there!
Which combo of wrenches, sockets, etc. do need to remove the two bolts so I can replace the O-rings! A the combination of the universal joint and a 10mm socket on my extended ratchet is too long and it hits the back of the engine block.
Which combo of wrenches, sockets, etc. do need to remove the two bolts so I can replace the O-rings! A the combination of the universal joint and a 10mm socket on my extended ratchet is too long and it hits the back of the engine block.
05-26-2016, 11:11 AM
#22
Three Wheelin'
R134A i'm told evaporates trough the seals and the old system its less dense than R12. I've been told that it either wont cool properly and then at all in a couple of weeks or it wont cool at all.
R152A seems a bit more dense so that sounds like a better idea..but i'm no expert so i'll use R437A in my car as it actually says its a direct replacement for R12.
R152A seems a bit more dense so that sounds like a better idea..but i'm no expert so i'll use R437A in my car as it actually says its a direct replacement for R12.
05-26-2016, 05:46 PM
#23
RL Community Team
Rennlist Member
Rennlist Member
So, should one convert from R12? I can still have mine filled with it...
However, my condenser is leaking. The replacement is 500 which I'm not willing to pay for.
There's this thread from V2 but shipping across the Atlantic is likely not included in his price, either:
https://rennlist.com/forums/924-931-...condenser.html
So how difficult is it to find another condenser and modify the bracket? For every other car the condenser is less than 100, as always.
How complicated is it to make new lines from/to the condenser?
Are there cheaper compressors that will fit? I hear sunden a lot.
Thanks gents!
However, my condenser is leaking. The replacement is 500 which I'm not willing to pay for.
There's this thread from V2 but shipping across the Atlantic is likely not included in his price, either:
https://rennlist.com/forums/924-931-...condenser.html
So how difficult is it to find another condenser and modify the bracket? For every other car the condenser is less than 100, as always.
How complicated is it to make new lines from/to the condenser?
Are there cheaper compressors that will fit? I hear sunden a lot.
Thanks gents!
05-26-2016, 08:14 PM
#24
Advanced
R134A i'm told evaporates trough the seals and the old system its less dense than R12. I've been told that it either wont cool properly and then at all in a couple of weeks or it wont cool at all.
R152A seems a bit more dense so that sounds like a better idea..but i'm no expert so i'll use R437A in my car as it actually says its a direct replacement for R12.
R152A seems a bit more dense so that sounds like a better idea..but i'm no expert so i'll use R437A in my car as it actually says its a direct replacement for R12.
05-26-2016, 10:55 PM
#25
I used this last summer: Enviro-Safe R134a AC Refrigerant + Dye 1 Can https://www.amazon.com/dp/B0081T3PP4..._SI6rxbS11NQ5Z
No change to my original R12 system and it worked great.
No change to my original R12 system and it worked great.
05-26-2016, 11:25 PM
#26
Burning Brakes
Thread Starter
Ok I got those 2 freakn o-rings that go into the firewall removed and new ones put on.
What a pain!!!
But I consider this one of my gratest achievements when it comes to this car. Not only was I able to get the o-rings off/on in a space that can only be described as located in a place worse than Hades Butthole but I did it in under an hour and without a single scratch/gouge/cut/knuckle buster or curse word - I really impressed myself with that last bit. I totally Macgyver'd it! It took 3 wobble extensions, some fishing line, a fishing weight and a trim removal tool.
What a pain!!!
But I consider this one of my gratest achievements when it comes to this car. Not only was I able to get the o-rings off/on in a space that can only be described as located in a place worse than Hades Butthole but I did it in under an hour and without a single scratch/gouge/cut/knuckle buster or curse word - I really impressed myself with that last bit. I totally Macgyver'd it! It took 3 wobble extensions, some fishing line, a fishing weight and a trim removal tool.
05-26-2016, 11:43 PM
#27
Addict
Rennlist Member
Rennlist Member
05-27-2016, 03:38 PM
#28
RL Community Team
Rennlist Member
Rennlist Member
However, generally I'm very much against using 30-year-old parts, I don't trust them.
05-27-2016, 04:18 PM
#29
Burning Brakes
More seriously, generally, if it's not a moving part, it can last a very long time.
05-27-2016, 07:59 PM
#30
RL Community Team
Rennlist Member
Rennlist Member
I'm constantly worried about the 30 year old stuff and they do **** me over at every turn they get. And this is with a car that was well cared for, so I can't imagine how the neglected ones can still drive and how anyone could possibly afford keeping multiple on the road. I'm being serious here.
My mechanic also strongly advised against it (for the condenser, I mean.). Still, I'll see what I find, there are not many 944 left around here, even in parts form.
